Liu Dongcao, Zhou Guang, Shi Hongbo, Chen Bin, Sun Xiaosong, Zhang Xuejun
Department of Urology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, China.
Iran J Biotechnol. 2020 Jan 1;18(1):e2270. doi: 10.30498/IJB.2019.85193. eCollection 2020 Jan.
Clear cell renal cell carcinoma (ccRCC) represents approximately 70% of RCC,as the most frequent histological subtype of RCC. MiR-138-5p, a tumor-related microRNA (miRNA), has been reported to be implicated in the diverse types of human malignancies, but its role in ccRCCremains unclear.
The study was designed to investigate the functional behaviors and regulatory mechanisms of miR-138-5p in ccRCC.
Quantitative real-time PCR and western blotting analyses were performed to determine the expression of miR-138-5p and TMEM40 in ccRCC tissues. Pearson's correlation coefficient was utilized to evaluate the correlation between miR-138-5p and TMEM40 expression. The function of miR-138-5p and TMEM40 in the cell proliferation, migration and invasion of ccRCC cells (786-O and ACHN) was assessed by CCK-8, colony formation, wound healing and transwell assay, respectively. A luciferase reporter assay was performed to confirm the direct binding of miR-138-5p to the target gene TMEM40.
We found the expression of miR-138-5p was significantly down-regulated, while TMEM40 was remarkably up-regulated in ccRCC tissues. TMEM40 expression was discovered to be inversely correlated with miR-138-5p expression in ccRCC tissues. Functional studies demonstrated that miR-138-5p overexpression or TMEM40 knockdown significantly suppressed ccRCC cell proliferation, migration and invasion in vitro. Notably, we experimentally confirmed that miR-138-5p directly recognizes the 3'-UTR of the TMEM40 transcript and down-regulated its expression in ccRCC cells.
Taken together, our findings provide the first clues regarding the role of miR-138-5p as a tumor suppressor in ccRCC by directly targeting of TMEM40.
透明细胞肾细胞癌（ccRCC）约占肾细胞癌（RCC）的70%，是RCC最常见的组织学亚型。MiR-138-5p是一种与肿瘤相关的微小RNA（miRNA），据报道它与多种类型的人类恶性肿瘤有关，但其在ccRCC中的作用仍不清楚。
本研究旨在探讨miR-138-5p在ccRCC中的功能行为和调控机制。
采用定量实时PCR和蛋白质印迹分析来确定ccRCC组织中miR-138-5p和跨膜蛋白40（TMEM40）的表达。利用Pearson相关系数评估miR-138-5p与TMEM40表达之间的相关性。分别通过CCK-8、集落形成、伤口愈合和Transwell实验评估miR-138-5p和TMEM40对ccRCC细胞（786-O和ACHN）增殖、迁移和侵袭的作用。进行荧光素酶报告基因实验以证实miR-138-5p与靶基因TMEM40的直接结合。
我们发现ccRCC组织中miR-138-5p的表达显著下调，而TMEM40显著上调。在ccRCC组织中发现TMEM40的表达与miR-138-5p的表达呈负相关。功能研究表明，miR-138-5p过表达或TMEM40敲低可显著抑制ccRCC细胞在体外的增殖、迁移和侵袭。值得注意的是，我们通过实验证实miR-138-5p直接识别TMEM40转录本的3'-UTR并下调其在ccRCC细胞中的表达。
综上所述，我们的研究结果首次揭示了miR-138-5p通过直接靶向TMEM40在ccRCC中作为肿瘤抑制因子的作用。
